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[英]Passing a variable or property value to a method in a JavaScript object returns “undefined”
[英]Javascript & HTML - Passing dropdown index value as object property returns undefined
我是這種語言的新手,但遇到了障礙。 我已經針對這個特定問題搜索了幾個小時,但似乎無法弄清楚為什么我的情況如此難以解決。 我確定我只需要一雙知道自己在看什么的眼睛。
我正在嘗試將下拉選擇的索引傳遞到我的 Code.gs 函數中,以便我可以在其他地方使用它來選擇電子表格中的某一行數據。 我設置了對象 driverPicked 並為其指定了選定的屬性,然后尋找選定的索引屬性。 由於我對此非常陌生,因此我很難理解像這樣嵌套屬性的后果,並且可以使用線索來解決如何解決“TypeError:無法讀取未定義的屬性‘selected’(第 39 行,文件“代碼”)”錯誤我已經有幾個小時了。
有很多類似的答案,但我無法確切地弄清楚它們如何適用於我 - 所以請原諒我!
var url = "REDACTED";
function doGet(e){
//var x = document.getElementById("driver").selectedIndex;
var driverIndex = userClicked();
var ss = SpreadsheetApp.openByUrl(url);
var ws = ss.getSheetByName("Results_2019");
var listDrivers = ws.getRange(4,1,ws.getRange("A3").getDataRegion().getLastRow(),1).getValues();
var infoHeading = ws.getRange(3, 1, 1, 8).getValues();
var driverInfo = ws.getRange(driverIndex, 1, 1 ,8).getValues();
var tmp = HtmlService.createTemplateFromFile("page");
tmp.title = "GLTC Driver List";
//tmp.listDrivers = listDrivers.map(function(r){r[0];});
tmp.listDrivers = [].concat.apply([], listDrivers);
tmp.infoHeading = [].concat.apply([], infoHeading);
tmp.driverInfo = [].concat.apply([], driverInfo);
tmp.driverIndex = driverIndex;
return tmp.evaluate();
}
function include(filename){
return HtmlService.createHtmlOutputFromFile(filename).getContent();
}
function userClicked(driverPicked) {
console.log(driverPicked);
var driverName = driverPicked.value;
return driverName;
}
<!DOCTYPE html>
<html>
<head>
<base target="_top">
<!--Let browser know website is optimized for mobile-->
<meta name="viewport" content="width=device-width, initial-scale=1.0"/>
<!--Import Google Icon Font-->
<link href="https://fonts.googleapis.com/icon?family=Material+Icons" rel="stylesheet">
<!-- Compiled and minified CSS -->
<link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/materialize/1.0.0/css/materialize.min.css">
<?!= include("page-css"); ?>
</head>
<body>
<h1><?= title; ?></h1>
<div class="input-field">
<select id="driver">
<option disabled selected>Choose Driver</option>
<? for(var i=0;i<listDrivers.length;i++){ ?>
<option class="selected">
<?= listDrivers[i]; ?>
</option>
<? } ?>
</select>
</div>
<h5><?= infoHeading; ?></h5>
<h5><?= driverInfo; ?></h5>
<h5><?= driverIndex; ?></h5>
<script>
document.getElementById("driver").addEventListener("change", doStuff); // add onchange listener to the select element instead of options
function doStuff(event) {
var driverPicked = {};
driverPicked.driver = event.target.value;
driverPicked.selected = event.target.options.selectedIndex;
userClicked(driverPicked);
}
</script>
<!-- Compiled and minified JavaScript -->
<script src="https://cdnjs.cloudflare.com/ajax/libs/materialize/1.0.0/js/materialize.min.js"></script>
<?!= include("page-js"); ?>
</body>
</html>
代碼的幾個問題:
select
元素使用change
事件而不是click
。doStuff
函數中訪問事件對象作為參數,而不是手動查詢 DOM 元素。 我不確定為什么需要獲取索引,但是為了獲取驅動程序的名稱,您可以這樣做:<div class="input-field">
<select id="driver">
<option disabled selected>Choose Driver</option>
<? for(var i=0;i<listDrivers.length;i++){ ?>
<option class="selected"> // use class instead of id here
<?= listDrivers[i]; ?>
</option>
<? } ?>
</select>
</div>
document.getElementById("driver").addEventListener("change", doStuff); // add onchange listener to the select element instead of options
function doStuff(event) {
var driverPicked = {};
driverPicked.driver = event.target.value;
driverPicked.selected = event.target.options.selectedIndex;
google.script.run.userClicked(driverPicked);
}
function userClicked(driverPicked) {
var driverName = driverPicked.value;
return driverName;
}
這是一個帶有一些模擬select
選項的可運行示例:
document.getElementById("driver").addEventListener("change", doStuff); // add onchange listener to the select element instead of options function doStuff(event) { var driverPicked = {}; driverPicked.driver = event.target.value; driverPicked.selected = event.target.options.selectedIndex; userClicked(driverPicked); } function userClicked(driverPicked) { console.log(driverPicked); var driverName = driverPicked.value; return driverName; }
<div class="input-field"> <select id="driver"> <option disabled selected>Choose Driver</option> <option class="selected"> Driver 1</option> <option class="selected"> Driver 2</option> </select> </div>
這里做了一些簡化。 主要的是,我不是通過google.script.run
調用該函數,而是直接調用它。
更新
我忘了包括在最初的回應中。 元素id
應該是唯一的。 如果您遍歷所有元素並且不更改它們的 id 值,那么您正在制作不正確的 HTML,並且函數getElementById(...)
將返回一個元素數組而不是僅返回一個元素數組(因此,其余代碼將不起作用正如預期的那樣)
見下面的演示
document.getElementById("driver").addEventListener("change", doStuff); function doStuff() { var driverPicked = {}; selectBox = document.getElementById("driver"); driverPicked = selectBox.options[selectBox.selectedIndex]; console.log('User changed value to: '); console.log(driverPicked); // will this work on other browsers? // google.script.run.userClicked(driverPicked); // I am using this instead for demo purposes userClicked(driverPicked); } function userClicked(driverPicked) { var driverName = driverPicked.value; var driverText = driverPicked.text; console.log('name/value: ' + driverName + ' text: ' + driverText); return driverName; }
<div class="input-field"> <select id="driver"> <option disabled>Choose Driver</option> <option value="1">One</option> <option value="2">Two</option> <option value="3">Three</option> <option value="4">Four</option> </select> </div>
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